This invention relates to a drive system for a motor vehicle comprising an internal combustion engine and a transmission.
Laid-open German specification DE 199 26 612 A1 discloses a belt drive for an internal combustion engine which has a crankshaft and a starter/generator. In this case, the crankshaft is provided with a first belt pulley and the starter/generator is provided with a second belt pulley. One belt wraps around both of the belt pulleys.
Laid-open German specification DE 33 32 515 A1 discloses an electric machine which has an associated converter appliance for driving purposes. The converter appliance is installed in a terminal box on a planar contact area. The terminal box is provided in the housing wall of the electric machine.
In drive systems for vehicles, little installation space is customarily available for the installation of, in particular, optional components, for example of a power electronics unit and/or a starter/generator. Additional installation often requires expensive reconstruction of the original drive system comprising an internal combustion engine and a transmission. A vehicle series usually has a wide range of internal combustion engines and transmissions. If the internal combustion engines have associated electric machines, in particular starter/generators, different embodiments of starter/generators are therefore also conceivable here in order to allow the vehicle series to be designed in a flexible manner. Belt-driven electric machines are customarily used for internal combustion engines with a small volume, whereas integrated electric machines are preferably used for internal combustion engines with a large volume. An integrated electric machine is understood to mean an electric machine which is arranged between an internal combustion engine and a transmission. In addition to the installation space required for the electric machine, the vehicle must also have enough installation space for a power electronics unit associated with the electric machine, and any energy stores, cooling units and further electrical components which may be present. The electric machine is preferably used for start/stop operation of the motor vehicle. Start/stop operation leads to a saving in terms of consumption and to a reduction in the environmental pollution caused by exhaust gases and emissions.
An object of the invention is to provide a drive system comprising an electric machine which requires as little installation space as possible.
This object is achieved by means of a drive system as claimed.
The drive system according to the invention is distinguished by a power electronics unit being integrated in the drive system in an installation space-saving manner. This results in a compact design and advantages in terms of packaging. The integrated design also results in improved electromagnetic compatibility since only short electrical lines are required. This is particularly favorable in modern vehicles which customarily contain a large number of electrical components, such as controllers. One refinement of the invention provides more installation space or volume for a power electronics unit even in the case of drive systems which have a large transmission bell housing and which are designed for a high starting torque.
Further advantageous refinements of the invention may be found in the subclaims and in the exemplary embodiments described in the following text with reference to the drawings.